Shifting jack-screw.



S. M. DUNLAP.

SHIPPING JAGK SCREW.

APPLICATION FILED MAY 22, 190B.

Patented Dec. 7, 1909.

rife

SYLVESTER M. DUNLAP, 0F DES MOINES, IOWA.

'SHIFTING JACK-SCREW.

Specification of Letters Patent.

Patented Dec. '7, 1909.

Application filed May 22, 1908. Serial No. 434,329.

To all whom it may concern:

Be it known that I, SYLvEsTER M. Don- LAP, a citizen of the United States, residing in Des Moines, county of Polk, and State of Iowa, have invented a new and useful Improvement in Shifting J ack-Screws, of which the following is a specification.

The object of my invention is to provide a means, simple, strong, durableand lnexpensive in construction of shifting, laterally, the position of a jackscrew and the weight it is supporting, after the sald welght has been placed thereon.

Another object is to provide a jackscrew, designed to support a heavy body, on wh ch or from which the said body may be easily moved.

My invention consists of certain details of construction hereinafter set forth, pointed out in my claims and illustrated in the accompanying drawings in which- I Figure I shows the lower or base portion on which the jackscrew proper is mounted; Fig. II shows the jackscrew proper; Fig. III shows a plan view of the upper removable portion designed to be mounted on the jackscrew proper; Fig. IV shows an inverted plan view of the jackscrew proper; Fig. V shows a vertical sectional view of my j ackscrew and attachment; and, Fig. VI shows a longitudinal sectional View of the base portion on which the. ackscrew is mounted and a portion of the body of the jackscrew also in section. 7

Referring to the accompanying drawings the reference numeral 10 is used to indicate a jackscrew, of'any ordinary type, provided, on two opposite sides and near the bottom of its body portion, with grooves, 11 and 12 respectively. Secured in the under surface of the said body portion and at right angles to the said grooves are rollers 13 mounted,

for rotary movement, the lower portions of their peripheries extending a very little lower than the said under surface of the body portion, all of the same being parallel, as illustrated.

The numeral 14 indicates an internally screw threaded opening extending centrally through the body portion parallel with the grooves 11 and 12 and obviously at right an-v gles to the said rollers 13.

The jackscrew 10 is mounted within a base 15 provided with a fiat bottom its two longitudinal sides 16 and 17 extending upwardly therefrom and curving inwardly so as to be adapted to form tracks to receive the grooves 11 and 12 respectively, and by this said means'my jackscrew is secured to the said .base, the rollers 13 engaging the bottom thereof. The two ends 18 and 19 of the base 15 extend upwardly in a vertical plane and are each provided with an oblong orifice, 20 and 21 respectively, similar in every respect and designed to be in line with the internally screw threaded opening 14.

The numeral 22 indicates a screw threaded shaft mounted, for rotary movement, in the oblong orifices 20 and 21 and extending through the opening 14 and designed to engage the screw threads in the said opening. On each end of the shaft 22, immediately outside the ends 18 and 19, are enlarged portions 23 and 24 respectively, provided with recesses or channels 25, designed to receive a rod or crowbar for turning the said shaft and immediately outside each of said enlarged portions the shaft 22 ends in a squared head adapted to receive a wrench designed to provide a further means of turning said shaft.

It is obvious from the foregoing description that by turning the shaft 22 the jackscrew will be moved laterally within the base 15 and it is equally obvious that the rollers 13 will greatly assist in the said movement. The object of constructing oblong orifices at 20 and 21 is to provide for a certain vertical movement of the shaft 22 within them.

The numeral 26 indicates the attachment which I secure to the upper portion of the jackscrew, said attachment being, by construction, of the exact size as the upper portion of said jackscrew and provided with a downwardly projecting flange 27, designed to engage the sides of the upper portion of the jackscrew, and to by this means hold the attachment in position 011 the jackscrew. In the upper surface of the attachment I have mounted, for rotary movement, parallel rollers 28 the upper portions of their peripheries projecting above the top of the said attachment. It is obvious that by this means a heavy weight, being supported by jackscrews of my construction, may, by application of power, be easily moved thereon.

Having thus described my invention what I claim and desire to secure by Letters Pat,- ent of the United States is:

1. A shifting jackscrew, comprising in combination a jackscrew provided with a opening and parallel rollers in its under surface; a base provided with inwardly inclined and upwardly projecting longitudinal sides and upwardly projecting ends provided with oblong slots; a screw threaded shaft and means for rotating said shaft; an upper portion designed to be secured on the upper surface of the jackscrew and parallel rollers in said upper portion, substantially as shown and described.

SYLVESTER M. DUN LAP. \Vitn esses ZnLL G. Ron, BLANCIIE Snoowiou. 

